The list sounds subjective, but it's actually the result of science: it's from a study by the University of Michigan, published in the U.S. National Library of Medicine, which looked into what foods were most likely to lead to a food addiction, and why.

Apparently, a big reason we keep going back for another slice is the cheese: It contains an ingredient called casein, a protein found in dairy products. When we digest cheese, it releases an opiate called casomorphin that lights up your dopamine receptors and makes you feel addicted—just like an actual addictive drug would do.

But casein isn't the only reason we love pizza. There's also pizza's combination of being high in fat—from cheese and olive oil—and refined carbs, from the crust. Nine out of ten foods at the top of the list of addictive foods were "highly processed and high in both fat and refined carbohydrates," according to the study (the one exception is soda, which has lots of refined carbs and processing, but little to no fat).

Science still, however, doesn't have an explanation for why Chicagoans continue to call their deep-dish casserole "pizza" (New York represent!).